Gianotti began working on liquid-argon calorimetry at the LHC in 1990 and continued that work for ATLAS when the collaboration began in 1992. Gianotti also worked on LEP2's supersymmetry search between 1996 and 2000.

She has been selected by CERN Council as the Organization’s next Director-General. The appointment will be formalised at the December session of Council, and Dr Gianotti’s mandate will begin on 1 January 2016 and run for a period of five years. She will be the first woman to hold the position of CERN Director-General.[3]

The ATLAS collaboration consists of almost 3,000 physicists from 169 institutions, 37 countries and five continents, and is the biggest detector ever built at a particle collider. Gianotti served as ATLAS physics coordinator from 1999 to 2003 and as deputy spokesperson to Peter Jenni from 2004 to 2009. She worked with the collaboration since its inception. After 18 years of working with CERN, Gianotti became 2009 the ATLAS experiment's spokesperson and coordinator, leading the lab's strategic planning and presenting findings to the international media.[8] On July 4, 2012, at the International Conference on High Energy Physics, Gianotti announced that a team at CERN had discovered a particle consistent with the Higgs Boson predicted by the Standard Model of physics.[9] She also was a finalist for the Time's Person of the Year for 2012.[10][11]

^Anon (2012). "We have it: History has been made with the discovery of a Higgs-like particle at CERN". Nature Physics8 (8): 575. doi:10.1038/nphys2404.

^Castelvecchi, Davide (2014). "Higgs hunter will be CERN's first female director: Italian physicist Fabiola Gianotti will take the reins at the European physics powerhouse in 2016.". Nature. doi:10.1038/nature.2014.16287.